Functional screening of drug target genes: m1 muscarinic acetylcholine receptor phenotypes in degenerative dementias.

Article Details


Weiner DM, Goodman MW, Colpitts TM, Feddock MA, Duggento KL, Nash NR, Levey AI, Brann MR

Functional screening of drug target genes: m1 muscarinic acetylcholine receptor phenotypes in degenerative dementias.

Am J Pharmacogenomics. 2004;4(2):119-28.

PubMed ID
15059034 [ View in PubMed

BACKGROUND AND OBJECTIVES: A number of recent studies surveying single nucleotide polymorphisms within the exonic regions of human genes have revealed a significant number of such variants, including many non-synonymous variants. This highlights the need to directly identify, within individual clinically well-defined patients, those variants that alter protein function as well as structure. We report on the development of a novel phenotypic screening process that combines high-throughput molecular cloning techniques with functional expression utilizing the cell-based assay R-SAT. METHODS: We applied the phenotypic screening process to an analysis of the m1 muscarinic acetylcholine receptor (CHRM1) gene in a cohort of 74 individuals, including 48 diagnosed with neurodegenerative disease, primarily Alzheimer disease, who have been stratified according to their clinical response to the acetylcholinesterase inhibitor donepezil. Phenotypic screening of the CHRM1 gene involved PCR-based amplification from genomic DNA and heterologous expression in mammalian cells. RESULTS: Phenotypic screening yielded functional responses to the agonist carbachol displaying a mean potency (-pEC(50)+/- standard deviation) of 5.8 +/- 0.2, which did not differ from that observed with expression of the wild-type receptor gene (6.0 +/- 0.3). No altered levels of constitutive receptor activity were observed. Dideoxy sequencing did not reveal any non-synonymous variants in the coding exon of this gene within this clinical cohort, while detecting three synonymous variants. CONCLUSION: The results confirm that the m1 receptor gene (CHRM1) is not highly polymorphic in the human population, suggesting that genetic variation within the coding exon of this gene is not a contributing factor to the clinical variability observed during treatment of dementia with cholinergic enhancement therapies.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
CarbamoylcholineMuscarinic acetylcholine receptor M1ProteinHumans